Researchers have used phylogenetic data to refine plant biogeographical categories in a new study. Scientists over the years have categorized the world into various floristic regions to help them understand plant diversity based largely on the plants present but also using paleoclimate and geological data. In a new study appearing in Nature Communications, researchers from Peking University and elsewhere fold additional phylogenetic data encompassing 12,664 angiosperm genera to refine these floristic regions. With this approach, they identified eight different floristic realms, which include three previously identified Holarctic, Neotropical, and Australian ones as well as the African, Novozealandic, Indo-Malesian, Chile-Patagonian, and Saharo-Arabian realms. Most of these realms, they add, formed by the early Cenozoic Era, and the differences between these regions are mostly driven by geographic isolation due to plate tectonics, rather than due to climatic effects. "Our global map of floristic realms provides a geographic framework for a wide variety of comparative studies in historical and ecological biogeography, macroecology, and systematics," the authors write.